1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
|
// SPDX-License-Identifier: GPL-2.0
/*
* Common functionality for RV32 and RV64 BPF JIT compilers
*
* Copyright (c) 2019 Björn Töpel <bjorn.topel@gmail.com>
*
*/
#include <linux/bpf.h>
#include <linux/filter.h>
#include <linux/memory.h>
#include <asm/patch.h>
#include <asm/cfi.h>
#include "bpf_jit.h"
/* Number of iterations to try until offsets converge. */
#define NR_JIT_ITERATIONS 32
static int build_body(struct rv_jit_context *ctx, bool extra_pass, int *offset)
{
const struct bpf_prog *prog = ctx->prog;
int i;
for (i = 0; i < prog->len; i++) {
const struct bpf_insn *insn = &prog->insnsi[i];
int ret;
ret = bpf_jit_emit_insn(insn, ctx, extra_pass);
/* BPF_LD | BPF_IMM | BPF_DW: skip the next instruction. */
if (ret > 0)
i++;
if (offset)
offset[i] = ctx->ninsns;
if (ret < 0)
return ret;
}
return 0;
}
bool bpf_jit_needs_zext(void)
{
return true;
}
struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
{
unsigned int prog_size = 0, extable_size = 0;
bool tmp_blinded = false, extra_pass = false;
struct bpf_prog *tmp, *orig_prog = prog;
int pass = 0, prev_ninsns = 0, i;
struct rv_jit_data *jit_data;
struct rv_jit_context *ctx;
if (!prog->jit_requested)
return orig_prog;
tmp = bpf_jit_blind_constants(prog);
if (IS_ERR(tmp))
return orig_prog;
if (tmp != prog) {
tmp_blinded = true;
prog = tmp;
}
jit_data = prog->aux->jit_data;
if (!jit_data) {
jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL);
if (!jit_data) {
prog = orig_prog;
goto out;
}
prog->aux->jit_data = jit_data;
}
ctx = &jit_data->ctx;
if (ctx->offset) {
extra_pass = true;
prog_size = sizeof(*ctx->insns) * ctx->ninsns;
goto skip_init_ctx;
}
ctx->arena_vm_start = bpf_arena_get_kern_vm_start(prog->aux->arena);
ctx->user_vm_start = bpf_arena_get_user_vm_start(prog->aux->arena);
ctx->prog = prog;
ctx->offset = kcalloc(prog->len, sizeof(int), GFP_KERNEL);
if (!ctx->offset) {
prog = orig_prog;
goto out_offset;
}
if (build_body(ctx, extra_pass, NULL)) {
prog = orig_prog;
goto out_offset;
}
for (i = 0; i < prog->len; i++) {
prev_ninsns += 32;
ctx->offset[i] = prev_ninsns;
}
for (i = 0; i < NR_JIT_ITERATIONS; i++) {
pass++;
ctx->ninsns = 0;
bpf_jit_build_prologue(ctx, bpf_is_subprog(prog));
ctx->prologue_len = ctx->ninsns;
if (build_body(ctx, extra_pass, ctx->offset)) {
prog = orig_prog;
goto out_offset;
}
ctx->epilogue_offset = ctx->ninsns;
bpf_jit_build_epilogue(ctx);
if (ctx->ninsns == prev_ninsns) {
if (jit_data->header)
break;
/* obtain the actual image size */
extable_size = prog->aux->num_exentries *
sizeof(struct exception_table_entry);
prog_size = sizeof(*ctx->insns) * ctx->ninsns;
jit_data->ro_header =
bpf_jit_binary_pack_alloc(prog_size + extable_size,
&jit_data->ro_image, sizeof(u32),
&jit_data->header, &jit_data->image,
bpf_fill_ill_insns);
if (!jit_data->ro_header) {
prog = orig_prog;
goto out_offset;
}
/*
* Use the image(RW) for writing the JITed instructions. But also save
* the ro_image(RX) for calculating the offsets in the image. The RW
* image will be later copied to the RX image from where the program
* will run. The bpf_jit_binary_pack_finalize() will do this copy in the
* final step.
*/
ctx->ro_insns = (u16 *)jit_data->ro_image;
ctx->insns = (u16 *)jit_data->image;
/*
* Now, when the image is allocated, the image can
* potentially shrink more (auipc/jalr -> jal).
*/
}
prev_ninsns = ctx->ninsns;
}
if (i == NR_JIT_ITERATIONS) {
pr_err("bpf-jit: image did not converge in <%d passes!\n", i);
prog = orig_prog;
goto out_free_hdr;
}
if (extable_size)
prog->aux->extable = (void *)ctx->ro_insns + prog_size;
skip_init_ctx:
pass++;
ctx->ninsns = 0;
ctx->nexentries = 0;
bpf_jit_build_prologue(ctx, bpf_is_subprog(prog));
if (build_body(ctx, extra_pass, NULL)) {
prog = orig_prog;
goto out_free_hdr;
}
bpf_jit_build_epilogue(ctx);
if (bpf_jit_enable > 1)
bpf_jit_dump(prog->len, prog_size, pass, ctx->insns);
prog->bpf_func = (void *)ctx->ro_insns + cfi_get_offset();
prog->jited = 1;
prog->jited_len = prog_size - cfi_get_offset();
if (!prog->is_func || extra_pass) {
if (WARN_ON(bpf_jit_binary_pack_finalize(prog, jit_data->ro_header,
jit_data->header))) {
/* ro_header has been freed */
jit_data->ro_header = NULL;
prog = orig_prog;
goto out_offset;
}
/*
* The instructions have now been copied to the ROX region from
* where they will execute.
* Write any modified data cache blocks out to memory and
* invalidate the corresponding blocks in the instruction cache.
*/
bpf_flush_icache(jit_data->ro_header, ctx->ro_insns + ctx->ninsns);
for (i = 0; i < prog->len; i++)
ctx->offset[i] = ninsns_rvoff(ctx->offset[i]);
bpf_prog_fill_jited_linfo(prog, ctx->offset);
out_offset:
kfree(ctx->offset);
kfree(jit_data);
prog->aux->jit_data = NULL;
}
out:
if (tmp_blinded)
bpf_jit_prog_release_other(prog, prog == orig_prog ?
tmp : orig_prog);
return prog;
out_free_hdr:
if (jit_data->header) {
bpf_arch_text_copy(&jit_data->ro_header->size, &jit_data->header->size,
sizeof(jit_data->header->size));
bpf_jit_binary_pack_free(jit_data->ro_header, jit_data->header);
}
goto out_offset;
}
u64 bpf_jit_alloc_exec_limit(void)
{
return BPF_JIT_REGION_SIZE;
}
void *bpf_jit_alloc_exec(unsigned long size)
{
return __vmalloc_node_range(size, PAGE_SIZE, BPF_JIT_REGION_START,
BPF_JIT_REGION_END, GFP_KERNEL,
PAGE_KERNEL, 0, NUMA_NO_NODE,
__builtin_return_address(0));
}
void bpf_jit_free_exec(void *addr)
{
return vfree(addr);
}
void *bpf_arch_text_copy(void *dst, void *src, size_t len)
{
int ret;
mutex_lock(&text_mutex);
ret = patch_text_nosync(dst, src, len);
mutex_unlock(&text_mutex);
if (ret)
return ERR_PTR(-EINVAL);
return dst;
}
int bpf_arch_text_invalidate(void *dst, size_t len)
{
int ret;
mutex_lock(&text_mutex);
ret = patch_text_set_nosync(dst, 0, len);
mutex_unlock(&text_mutex);
return ret;
}
void bpf_jit_free(struct bpf_prog *prog)
{
if (prog->jited) {
struct rv_jit_data *jit_data = prog->aux->jit_data;
struct bpf_binary_header *hdr;
/*
* If we fail the final pass of JIT (from jit_subprogs),
* the program may not be finalized yet. Call finalize here
* before freeing it.
*/
if (jit_data) {
bpf_jit_binary_pack_finalize(prog, jit_data->ro_header, jit_data->header);
kfree(jit_data);
}
hdr = bpf_jit_binary_pack_hdr(prog);
bpf_jit_binary_pack_free(hdr, NULL);
WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(prog));
}
bpf_prog_unlock_free(prog);
}
|